Walk: Pokéwalker
Its base catch rate is 45 out of 255 (higher is easier); the catch rate calculator works out your odds with each ball. For the look, the best colour match is Repeat Ball or Fast Ball.
Evolution: Magby → Magmar (Level 30) → Magmortar.
Magby in every game · Pokémon HeartGold & SoulSilver interactive map (Johto & Kanto)